Intro
13%
Running forge dies: why this course exists
The same die, built to the same print and treated to the same spec, lasts 30K hits in one shop and 120K hits in another. The spread lives in four operator-controlled levers, and that gap is the subject of this course.
A closed-die forge shop runs two presses on the same crankshaft job. Same H13 die design, same vendor, same nitride cycle, same drawing revision. Press 1 averages 30,000 hits per die before pull. Press 2 averages 120,000 hits per die before pull. Both shops blame the vendor. The vendor certificates come back clean: same substrate hardness, same case depth, same compound-layer thickness, same dimensional check. The die that lasts four times as long is not a different die. It is a different run.
This course is about that 4x gap. Courses 1 through 3 built the die. Course 1 covered the surface-treatment vocabulary. Course 2 covered nitriding in depth, including the witness coupon, the Kn control loop, and what to demand on a vendor certificate. Course 3 covered the build itself: steel selection, heat treat, geometry, and the trade between a deep diffusion zone and a brittle compound layer. By the end of Course 3, the die is bolted into the press. That is where Course 4 starts.